The rotary type prime mover of the present invention is an improvement of the prime mover which is the subject of U.S. application Ser. No. 236,289, filed Feb. 19, 1981, which in turn is a continuation-in-part of U.S. application Ser. No. 37,333, now abandoned.
In the device of said application, however, each cycle of induction, compression, firing and exhaust is performed in one casing. That is to say, the opening or closing of the casing, or the induction or exhaustion of air is performed in one casing.
But there are some disadvantages in the device of said application. Both the induction valve and the exhaust valve of the said device tend to wear out and also tend to get out of order so they are not opened or closed at an exact time. Thus, it is difficult for the internal combustion engine of the said application to maintain air-tightness and to perform its operation efficiently. In order to overcome such disadvantages, the present inventor made a further study of this engine, which resulted in the present invention.